1. Field of the Invention
The invention relates generally to a method of manufacturing polymer nano particle, and more particularly to, a method of manufacturing polymer nano particle containing two-photon absorption compound at its central portion.
2. Description of the Prior Art
Two-photon adsorption is defined to be a switching from a ground state to an excitation state due to consecutive absorption of two consecutive photons (where the sum of the two consecutive photo optical energy is same or greater to/than the energy gap of a non-linear optical material) having the energy smaller than the energy gap of the non-linear optical material.
The degree of two-photon absorption is proportional to the product of two-beam intensity. Therefore, absorption occurs only at a portion where the beam is focused. As a result, it is possible to define photochemical phenomenon due to two-photon absorption excitation in three-dimension. If this two-photon absorption is applied to application fields such as a three-dimensional optical memory, an up-conversion lasing, an optical power limiting, and the like, a common method of manufacturing an actual two-photon absorption medium includes optically distributing transparent polymer, etc. into a molecular unit. In this method, however, a gathered substance in which two-photon absorption compounds are physically coupled is formed due to a thermal effect and the difference in the polarity between two-photon absorption compound and optically transparent polymer. If the size of the two-photon absorption compound is greater than the wavelength of a visible ray region by {fraction (1/10)}, the gathered substance acts to scatter the beam, so that the beam does not penetrate into the medium in space. Further, in the application fields such as two-photon absorption excitation luminescence or laser oscillation, or the like, there is a problem that the luminescence and laser oscillation efficiency are abruptly reduced as the size of the two-photon absorption compound becomes larger. In order to preventing reducing the scattering and luminescence efficiency, it is required that the amount of dispersion of the two-photon absorption compound be reduced. However, this results in decreased two-photon absorption and the efficiency of a phenomenon accordingly.
The present invention is contrived to solve the above problems and an object of the present invention is to provide a method of manufacturing polymer nano particle containing photon absorption compound enough to cause an optical scattering at the central portion of the polymer nano particle and thus capable of controlling two-photon absorption wavelength.
In order to accomplish the above object, a method of manufacturing polymer nano particle according to the present invention, is characterized in that it comprises the steps of dispersing a monomer for forming polymer nano particle and two-photon absorption compound into a solvent; supplying a given gas while stirring the solvent in which the monomer and the two-photon absorption compound are dispersed at a given temperature, in order to remove the dissolved oxygen contained in the solvent; supplying polymerization initiators into the solvent while stirring the solvent in which the monomer and the two-photon absorption compound are dispersed at a given temperature; and polymerizing the monomer for a given period of time while stirring the solvent in which the monomer and the two-photon absorption compound are dispersed at a given temperature.
Further, in order to accomplish the above object, a method of manufacturing polymer nano particle according to the present invention, is characterized in that it comprises the steps of dispersing a monomer for forming polymer nano particle, two-photon absorption compound and surfactant into a solvent; supplying a given gas while stirring the solvent in which the monomer, the two-photon absorption compound and surfactant are dispersed at a given temperature, in order to remove the dissolved oxygen contained in the solvent; supplying polymerization initiators into the solvent while stirring the solvent in which the monomer, the two-photon absorption compound and surfactant are dispersed at a given temperature; polymerizing the monomer for a given period of time while stirring the solvent in which the monomer, the two-photon absorption compound and surfactant are dispersed at a given temperature, thus forming polymer nano particle; and removing the surfactant adhered to the surface of polymer nano particle using a given solvent.